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Unformatted text preview: Summary 461 Based on the discussion above, it would appear that the wavelength plane ap- proach offers a cheaper alternative to large-scale nonblocking optical switches. How- ever, we did not consider how to optimize the number of add/drop terminations (which would be transponders or O/E interfaces on electrical switch cores). Both Figure 7.13 and Figure 7.14 assume that there are sufficient ports to terminate all WF signals. This is almost never the case, as only a fraction of traffic will need to be dropped, and the terminations are expensive. Moreover, observe that if we indeed do need WF terminations on an electrical switch, the best solution is to use the electrical core configuration of Figure 7.11(a), without having the wavelength plane switches! If we have a total of T terminations, with all of them having tunable lasers, and we would like to drop any of the WF signals, this requires an additional T × WF optical switch between the wavelength plane switches and the terminations, as shown in Figure 7.15. In contrast, with a large nonblocking switch, we would simply connectin Figure 7....
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- Spring '09
- Electronics, Network switch, switch, Multiplexing, Crossbar switch, Fiber-optic communications